Telephone-transmitter.



PATENTED OCT. .3, 1905.

J. PRINCE.

TELEPHONE TRANSMITTER.

APPLICATION FILED AUG.1B,1902.

Z SHEETS SHEET J //v vav TUFr VWTNESSES WZV W PATENTED OCT. 8, 1905.

J. PRINCE.

TELEPHONE TRANSMITTER.

APPLICATION FILED AUG. 18,1902.

2 SHEETS-SHEET 2.

.r. WIIAVIIIIIITWFH l/V/ T/VES'SES JEROME PRINCE, OF MIL AND MESNE ASSIGNM PORATION OF THE DISTRICT OF FORD, MASSACHUSETTS, ASSIGNOR, BY DIRECT ENTS, TO PRINCE TELEPHONE COMPANY, A COR-- COLUMBIA.

TELEPHONE-TRANSMITTER.

Specification of Letters Patent.

Patented Oct. 3, 1905.

Application filed August 18, 1902 Serial No. 120,024.

To II/ZZ whum/ it 'ntrly calmer/1.:

Be it known th at I, JEROME PRINCE, of Milford, in the county of \Vorcester and State of Massachusetts, have invented certain new and useful Improvements in Telephone-Transmitters, of which the following is a specification.

The object of this invention is to provide a highly sensitive electric telephon and efficient transmitter for es; and it relates more specif- IO ically to a transmitter having within its casing and ad acent to the mouthpiece and diaphragm a hollow cylindrical resonant chamher of vitreous mounted longitu or other suitable material dinally or endwise with reference to the diaphragm, the effect of which cylinder or reson ator is to impart greater delicacy and also strength of vibration to the diaphragm and to increase the effectiveness of the entire transmitting apparatus.

My invention also relates to a transmitter provided with a variable resistance consisting t granular carbon together with magnetic iron mingled, said materials being interposed between two elec trodes included in the circuit,

one of said electrodes being attached to the inner side of the ing supported by connections with the casing and held in a fixed position.

In the accomp a longitudinal ce transmitter. Fi

diaphragm and the other beanying drawings, Figure 1 is ntral sectlon of my improved g. 2 1s a transverse sectlon on the line 2 2 of Fig. 1 looking to the left. Fig. 3 is a sectional view of the microphone and adjacent parts enlarged and disconnected.

Fig. A is a top plan view of the instrument, the cover being removed and parts 1n section.

(The location of battery 13 is changed to better represent the wiring arrangement.)

The casing 5 is of suitable size and shape to contain the parts and may be arranged, by removing screws or otherwise, to open at one side for convenient access, or a mere supportting-frame may be substituted. The mouthpiece 6 is of ordinary form and connected to an annular collar 7 by an intermediate flaring metallic neck 8.

The metallic collar 7 is securely attached to the frame or ca inner end, forini ceive the end of which constitute forcingchamber in Figs. 1 and I,

i this chamber is given by a metal cap or disk I 10 and by two screw-rods 11, extending from the rear end of the casing 5. The cap or disk 10, if used, will have an enlarged central opening for passage of the conducting-wires 12 and 12, which suitably connect the diaphragm and collar 7 with the battery 13 and other parts. The forked lever 14. Fig. 2, for support of the receiver (not shown) is pivoted at 15 and furnished with a spring 16. This clevice serves, as usual, to make the battery operative on removal of the receiver from the hook or lever 14: and inoperative at other nects the receiver to the instrument in an obvious manner. The induction-coil 18 is wired and arranged as usual.

The diaphragm 20 is formed of a sensitive metallic plate with an integral central cup, the flat bottom of which faces the opening from the mouthpiece. IVithin this cup are two thin magnetized disks or electrodes 21, separated by a body 22 of finely-granulated carbon and magnetic iron mingled. An insulating plate or sheet of mica 37, back of the innermost disk, extends outwardly beyond the walls of said cup. A flat metallic ring 24, secured to the diaphragm adjacent to the walls of the cup, overlaps the edges of themica disk and. holds the parts in place. The conducting-- Wire 12 is connected. toa short arm 25', pro+- jecting from; this. ring. A central stem 26, projecting-from theinnermost disk 21 through. the mipa sh eet 37jand through a thimble 38; connects said disk to a metal cross-piece or bridge 27, interposed between the collar 7 and the broadened neck 8. A rubber ring 28 incloses the edges of the diaphragm and affords the desired insulation. Flat metal springs 29, interposed between the cross-piece 27 and ring 28, extend each way to hold the diaphragm, as seen in Fig. 2.

By referring to Fig. 4 it will be seen that Wire l2 is connected with the diaphragm of the microphone by means of the short arm. 25 (shown also in Figs. 2 and 3) and wire 12" is connected to collar 7. The circuit is as follows: from the microphone-ring 24;, with its arm 25, through wire 12 to forked lever 14, which furnishes connection to wire 30 when the receiver is off the hook, thence by: wire 30, through primary winding of coil 18, and wire 31 to binding-post 32, and thence row to the line, from the line back to binding-post 33, across to binding-post 34:, thence to the receiver by wire 17, and back to binding-post 35, through secondary winding of coil 18, and by wire 36 to battery 13, and thence by wire 12" to collar 7, cross-bar 27, and the microphone-stem 26.

The drawings represent in Figs. 1, 2, and 4 a portable instrument in which a dry battery 13 is inclosed within the casing for convenience to make the device portable. For permanent instruments connected with a central energy system the battery 13 would be omitted and the circuit be direct to collar 7.

Short-circuitingfrom the microphone to the metallic collar '7 is prevented by the marginal insulating-band 28 and the central mica disk 37, which bridges the open center of ring 24, leaving a space between the inner edge of said ring and the flange of thimble 38, passing through cross-bar 27. (See Figs. 3 and 4.)

In my improved transmitter the electrodes 21 are small thin disks of limited magnetic force, and by employing the natural magnetic ore-granules this limited magnetic force of the disks is supplemented by the natural magnetic force of the granules, while the polarity of the native-ore granules mingled with carbon particles sufiices to sensitize or energize the microphone from within. True magnetic iron is a force in and of itself in a diaphragm-chamber. I utilize this force emanating from said chamber, the benefit derived therefrom being additional to and irrespective of any induced magnetism from the disks. Oommingling the materials in the chamber without comminuting or closely packing them gives peculiar clearness and power of transmission to the instrument.

I claim as my invention- 1. In a telephone-transmitter,the casing and a suitable mouthpiece and diaphragm, in combination with a vitreous reinforcing-chamber open to the air on all sides for free vibration, made distinct from the diaphragm, and suitably secured within the casing, substantially as set forth.

2. In a telephone-transmitter, the frame or casing an annular collar therein and a suitable mouthpiece and diaphragm connected thereto, in combination with a cylindrical glass reinforcing-chamber mounted endwise on said collar, substantially as set forth.

3. In a telephone-transmitter, the frame or casing having an annular collar and the mouthpiece, neck and diaphragm connected thereto, in combination with a tubular glass reinforcing-chamber mounted endwise on such collar and with cond ucting-wires through said chamber from the diaphragm and said collar, substantially as set forth.

4. In a telephone-transmitter, the frame or casing having an annular metallic collar and a mouthpiece, neck and diaphragm connected thereto, in combination with a tubular reinforcing-chamber mounted endwise on said collar and with a terminal cap or disk covering its outer end, substantially as set forth.

In a telephone-transmitter, the frame or casing having an annular metallic collar and a mouthpiece and diaphragm connected thereto, in combination with a tubular glasschamber mounted endwise on said collar and a battery adjacent to said chamber and electrically connected with said collar and diaphragm, substantially as set forth.

6. In a telephone-transmitter the frame or casing, the inclosed tubular reinforcing-chamber, the metallic collar carrying said chamber, and suitable conducting-wires, in combination with a diaphragm having an integral cup-like depression, magnetized disks therein with in termediate granular magnetic material, and a covering-ring fixed to the diaphragm and pro- .vided with a projecting arm for connection with one conducting-wire, the other wire being connected to said collar, substantially as set forth.

7. In a telepholie-transmitter, the combination of a vibratory diaphragm, a resistancechamber carried thereby, front and back electrodes included in the electric circuit within said chamber, and a body of variable-resistance material composed of granular carbon and natural magnetic iron mingled disposed within said chamber and between said electrodes, substantially as set forth.

8. In a telephone-transmitter, the combination of a vibratory diaphragm formed with a central cup or chamber, front and back electrodes consisting of magnetized disks included in the electric circuit within said chamber, the former mounted on the diaphragm, the latter held in a fixed position by supports connected with the casing, and a variable resistance composed of particles of granulated carbon and natural magnetic iron mingled interposed between said electrodes, substantially as set forth.

9. In a telephone-transmitter, the combination of a vibratory diaphragm formed with a central cup or chamber, front and back electrodes included in the electric circuit within said chamber, the former mounted on the diaphragm, the latter supported by connections with the casing, a sheet of non-conducting-material forming an inner wall for said chamber, and a variable resistance composed of particles of granulated carbon and natural magneticiron mingled contained between said electrodes, substantially as set forth.

In testimony whereof I have affixed my signature in presence of two witnesses.

JEROME PRINCE.

IVitnesses.

A. H. SPENCER, H. W. LADD.

ICC 

